[moderation] [serial?] KCSAN: data-race in __tty_hangup / io_file_get_normal

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: dd9b004b7ff3 Merge tag 'trace-v6.19-rc1' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10dccb1a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b319ff1b6a2797ca
dashboard link: https://syzkaller.appspot.com/bug?extid=ff47261bf0e5233fd700
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
CC: [gre...@linuxfoundation.org jiri...@kernel.org linux-...@vger.kernel.org linux-...@vger.kernel.org]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9e79d07095a9/disk-dd9b004b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/17768b8878a0/vmlinux-dd9b004b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2990b6178ed7/bzImage-dd9b004b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ff4726...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __tty_hangup / io_file_get_normal

write to 0xffff888103de0d88 of 8 bytes by task 7956 on cpu 0:
__tty_hangup+0x1ef/0x540 drivers/tty/tty_io.c:612
tty_vhangup drivers/tty/tty_io.c:691 [inline]
tty_ioctl+0x601/0xb80 drivers/tty/tty_io.c:2732
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xce/0x140 fs/ioctl.c:583
__x64_sys_ioctl+0x43/0x50 fs/ioctl.c:583
x64_sys_call+0x14b0/0x3000 arch/x86/include/generated/asm/syscalls_64.h:17
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xd8/0x2c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888103de0d88 of 8 bytes by task 7953 on cpu 1:
io_is_uring_fops io_uring/io_uring.c:3357 [inline]
io_file_get_normal+0x3b/0x180 io_uring/io_uring.c:1990
io_assign_file+0x9e/0x200 io_uring/io_uring.c:1767
io_issue_sqe+0x40/0xa80 io_uring/io_uring.c:1812
io_queue_sqe io_uring/io_uring.c:2042 [inline]
io_submit_sqe io_uring/io_uring.c:2320 [inline]
io_submit_sqes+0x78b/0x11b0 io_uring/io_uring.c:2434
__do_sys_io_uring_enter io_uring/io_uring.c:3280 [inline]
__se_sys_io_uring_enter+0x1bd/0x1a30 io_uring/io_uring.c:3219
__x64_sys_io_uring_enter+0x78/0x90 io_uring/io_uring.c:3219
x64_sys_call+0x27e4/0x3000 arch/x86/include/generated/asm/syscalls_64.h:427
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xd8/0x2c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffffffff858a6020 -> 0xffffffff858a5f10

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 7953 Comm: syz.3.1130 Tainted: G W syzkaller #0 PREEMPT(voluntary)
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
==================================================================


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